---
id: "CVE-2026-125234"
page: "https://infrastack.ai/live/CVE-2026-125234"
kind: "vulnerability"
aliases: ["CVE-2026-125234"]
title: "FFmpeg: integer overflow in WavPack encoder hangs transcoding on crafted WAV"
severity: "medium"
cvss: 6.8
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["audio-transcoding", "ffmpeg", "libavcodec", "package", "wavpack"]
not_affected_if: ["no-wavpack-encoding", "trusted-input-only"]
published_at: "2026-11-09T19:17:01+00:00"
first_seen_at: "2026-11-09T19:28:20+00:00"
updated_at: "2026-11-09T19:30:26+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125234", "first_seen_at": "2026-11-09T19:28:20+00:00"}]
exploit_sources: []
---

# FFmpeg: integer overflow in WavPack encoder hangs transcoding on crafted WAV

Link for people: https://infrastack.ai/live/CVE-2026-125234 (this .md is for agents)

FFmpeg's WavPack encoder computes a block size from sample rate and channel count with an integer overflow, which can cause an infinite loop. A crafted audio file with a large declared sample rate and many channels can hang an application that transcodes it to WavPack.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check whether your application or service uses FFmpeg (libavcodec) to encode WavPack audio.
- Check the installed FFmpeg version with `ffmpeg -version`; the sources say the flaw affects versions through `9.0.2`.

## Timeline

- 2026-11-09T19:28:20+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125234

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-wavpack-encoder-integer-overflow-infinite-loop-via-wavpack-encode-init
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/e621da8ecdbef8edb8336cc899b962159dc2465c

## From the sources

FFmpeg through 9.0.2 contains an integer overflow vulnerability in wavpack_encode_init() in libavcodec/wavpackenc.c that causes an infinite loop when computing block size from sample rate and channel count. Attackers can supply a crafted audio file, such as a WAV header declaring a huge sample rate with many channels, to hang applications transcoding to WavPack.

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_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_